Safety investigators looking into the catastrophic Baltimore bridge collapse will seek to establish whether contaminated fuel played a part in the disaster, sources told The Wall Street Journal. The Dali cargo ship was reportedly hit by propulsion and steering power issues before it crashed into the Francis Scott Key Bridge early Tuesday. While blackouts at sea are relatively rare, they have happened before and are considered a serious hazard for ships, according to the Journal. Naval architect Fotis Pagoulatos said contaminated fuel can cause problems for a ship’s main power generators and that a blackout can lead to a loss of propulsion. An officer on board the Dali said one of the ship’s engines “coughed and then stopped” before the collision, adding that there wasn’t enough time to drop anchors to prevent the drifting. Six contractors who were working on the bridge at the time of its collapse are presumed to be dead, Coast Guard Rear Admiral Shannon Gilreath said Tuesday evening.